1. Field of the Invention
The present invention relates to power supplies, and more particularly for protection of an electronic instrument from the power supply.
2. The Background
The use of power supplies for providing power to an electronic equipment or instruments is well known. Such power supplies commonly have a power cord, such as a standard IEC-type cord, removably attached to the power supply for providing power to the power supply. Commonly, a rear face of the power supply is provided with electrical connectors which may be removably attached to corresponding connectors on a back plane of the electronic instrument in order to supply power to the electronic instrument.
It is also known that the power supply must not generate power while it is being attached to or removed from the back plane of the instrument, since such connection and removal while powered may cause arcing of the assembly, which may result in damage to the electronic instrument and/or to the power supply.
The simple solution to this problem is, of course, either to turn a power switch off on the power supply, or to remove the power cord from the power supply, after which the power supply may be safely attached to or removed from the back plane without a problem. However, the connection and detachment of the power supply may be done by an operator of the equipment who is unfamiliar with this procedure, or unwilling to comply with it, and thus may attach or disconnect the power supply with the power supply in full operation. In addition, an operator may be handling the equipment who is familiar with this procedure, but who inadvertently attaches or removes the power supply while it is operating. Hence, it would be desirable to make it impossible to attach or remove to the power supply to or from the back plane while the power supply is generating power in order to prevent this result.